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Copper air lines- 50/50 or 95/5 solder?

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
I'm done tripping over air hoses. Got a truckload of type L copper and Unistrut. Air lines are happening next week. Does the old 50/50 solder make a better joint than the lead free stuff? I can order the 50/50 if it's better.

EDIT: Just remembered a hoarder friend gave me a crate of old solder awhile back. Found it and there's 30 pounds of 50/50 in there!
 
I think the tin/lead flows a little easier, but both will form a joint that will hold any reasonable air pressure. You can use silver solder, but it gets so hot doing it that the pipe is annealed and that reduces the pressure rating (still not a problem for shop air).
 
I think the tin/lead flows a little easier, but both will form a joint that will hold any reasonable air pressure. You can use silver solder, but it gets so hot doing it that the pipe is annealed and that reduces the pressure rating (still not a problem for shop air).

I'm not interested in silver soldering it. If the 50/50 is fine I will grab some flux and use what I have.
 
I belive his 95/5 solder has silver in it. But it is not the same as silver soldering. 50/50 is much easier to flow and more then strong enough.
Bill D
 
For just air lines? Type L and lead/tin solder is perfectly fine. My company (a Fortune 100 place) uses exactly that so I did the same in my personal shop. Can't beat it. Company wouldn't use it if there were any chance of real issues as the liability would scare them off. You can use the lead-free too as it is easier to find, but it melts higher and is a bit harder to use.
 
To the OP, personally, I would use the blue plastic stuff, made for air distribution. Much, much easer to put together. (If I used copper, I would tend to go with type K And silver braze it)

Obvious question no one asked, what’s your max working pressure? “Shop air” could be 90 psi, or 190 psi. The former you are fine with soft solder, the latter, no not So much.
 
If the joint is soldered correctly, 50/50 wil be way stronger than needed. I do plumbing repairs as a side gig a lot in rehab houses that have been sitting for years and have seen plenty of ballooned and burst frozen copper water lines with intact solder joints. Very rarely see pulled apart solder joints unless they were improperly soldered.

Steam lines are a different story since steam gets a lot hotter than water or normal air lines ever will and can potentially melt the solder.
 
Use Hamlet or Hoke compression fittings instead of the old solder method.

The 90 degree Hamlets are machined internally to have uniform internal radius to minimize turbulence. The Hoke ones are bored on one side
and then bored from the other side leaving a non-uniform passage.
 
I used regular plumbing solder,it is strong enough for 120 psi, 17 years, 150 feet of lines, 10 drops,no leaks or failures.
I had not thought about the heat near the compressor, originally I had rubber and now the piece of cooper was done by someone else,so it could be different solder
 
To the OP, personally, I would use the blue plastic stuff, made for air distribution. Much, much easer to put together. (If I used copper, I would tend to go with type K And silver braze it)

Obvious question no one asked, what’s your max working pressure? “Shop air” could be 90 psi, or 190 psi. The former you are fine with soft solder, the latter, no not So much.

I think the cost of that stuff is nuts and it doesn't look very good. I can get same results as that stuff for 1/10th the price using air brake tubing.

I've used PVC (very dumb, learned that lesson), copper and air brake tubing to plumb shop air in places I have leased. Now I own my building and I like copper for ease of install, ease of modification and it looks better than air brake tubing. `

My shop consists of two rehabbed old barns each about 1800 sq ft with a 65x65 20' tall steel building with a 5 ton bridge crane built between and connected to them. There's a lot of air line to run.

For compressors I have two brand new 5HP Quincy QR325's feeding into a new 120 tank with auto drain and a refrigerated dryer. All that is in it's own room. That will feed a loop of 1" copper around the crane runway in the main building with 1/2" drops down the support columns to quick connects every 20 feet.

My biggest air consumer is air blast milling steel. I run the tank to 150 PSI and plan to set the lines at 100-120 or whatever works best.
 
I personally use type L and silver solder the 175 psi lines. When the pressure drops to 120 psi or less I solder with 50/50.

Copper does a much better job of cooling the air thus letting the water separators do their job. If you have air dryers then using copper is not important in my opinion. I used to suffer greatly with wet air until I improved my air lines - did it all by using copper lines to cool the air before it hit the water separators. And I followed all the recommended practices for installing the lines including proper slope and taps.
 
To the OP, personally, I would use the blue plastic stuff, made for air distribution. Much, much easer to put together. (If I used copper, I would tend to go with type K And silver braze it)

Personally, I think the plastic stuff sucks. It is expensive to begin with. And, then it hits you again when you have to fix it in a couple years.
There is also no reason for anything more than type-L soldered with any old solder that will flow with propane (by somebody who knows how to solder).
Unless you are running dangerous pressures? Upwards of 200psi. Pretty sure at that point, a guy best be screwing pipe together.

Copper will outlive most anything for air lines. And, do it reliably. I have never, not one single time, in the miles and miles of copper air lines I have ran,
had one single leak in a sweat fitting. Copper is the way to go if you like shit done permanently.
 
any old solder that will flow with propane (by somebody who knows how to solder).

My 2 cents on that.. Soldering, Brazing, even welding, if you are out of practice and especially if you are new at it.. PRACTICE.

For me anyways, its amazing how BAD those first joints are if I haven't soldered in a while.. After a few "practice" pieces, it all just falls into place, and I can tear through it in no time and it actually comes out good.
 
An annular/plug brush, tinned flux, a decent torch and appropriate solder make it idiot proof. I have 200+ feet of 3/4” copper with at least 10 1/2” drops, (each of which has a quick connect and a ball valve drain, all sweated connections) and three permanently plumbed 50’ hose reels. I put it all in more than 10 years ago, Nothing leaked then or now. If my compressor ever cycles when I’m not actively using air, I go find whatever I left plugged in, because the tubing and installation doesn’t leak at all.
 
I personally use type L and silver solder the 175 psi lines. When the pressure drops to 120 psi or less I solder with 50/50.

Copper does a much better job of cooling the air thus letting the water separators do their job. If you have air dryers then using copper is not important in my opinion. I used to suffer greatly with wet air until I improved my air lines - did it all by using copper lines to cool the air before it hit the water separators. And I followed all the recommended practices for installing the lines including proper slope and taps.

Is the proper way to slope the supply line towards the drops slightly?


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My 2 cents on that.. Soldering, Brazing, even welding, if you are out of practice and especially if you are new at it.. PRACTICE.

For me anyways, its amazing how BAD those first joints are if I haven't soldered in a while.. After a few "practice" pieces, it all just falls into place, and I can tear through it in no time and it actually comes out good.

If helping someone new at it, my #1 recommendation is DON'T overheat! Bring the heat up slowly and keep pulling the torch away and touching with the solder. You want just barely above the melting point or the flux may burn. If that happens the solder will be repelled rather than wetting the joint. Once it melts don't apply more heat unless it isn't melting anymore, and then only a few seconds at a time. Keep the heat focused where you want the solder to go. Also CLEAN the tubing to bright copper inside and out. Use tinning flux for easy joints. Lots of little tips that are useful for those new to it.
 
Is the proper way to slope the supply line towards the drops slightly?


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I followed the advice of what I found on the internet but unfortunately I can't find that site at this time.

The slope is away from the compressor. At the end of that sloped line you put a drain port to drain the water accumulated in that line. The recommendation I found and followed was that if you don't have an air dryer to have minimum of 50 feet of metal piping before the first drop and before any water separator - the bigger the diameter the better. I went with 3/4 and wish my first 50 feet were 1 inch but mine works. I zig zagged a bunch of tubing to make the 50 feet. Trick I learned later after I already installed mine was to put an expansion chamber in - about 2" or bigger pipe for a few inches and then neck back down to normal size. I understand that per thermodynamics that will help cool the air (I didn't do too good in Thermodynamics - all these years later I remember that Dr. Kowalski gave me a C in the class and he was generous - LOL!).

The other really important aspect is when doing the drop to go up first a few inches and then drop your leg down. At the end of each drop put a drain port - tap off the down legs for your connection - never from the bottom of the drop legs.
 








 
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